ST2 is an interleukin-1 receptor family member with transmembrane (ST2L) and soluble isoforms (sST2 or soluble ST2) (Iwahana et al., Eur. J. Biochem. 264:397-406, 1999). Recently published articles describe the current knowledge on the relationship of ST2 to inflammatory diseases (Arend et al., Immunol. Rev. 223:20-38, 2008; Kakkar et al., Nat. Rev. Drug Discov. 7:827-840, 2008; Hayakawa et al., J. Biol. Chem. 282:26369-26380, 2007; Trajkovic et al., Cytokine Growth Factor Rev. 15:87-95, 2004). Circulating concentrations of human soluble ST2 are elevated in patients suffering from various disorders associated with an abnormal type-2 T helper cell (Th2) response, including systemic lupus erythematosus and asthma, as well as in inflammatory conditions that are mainly independent of a Th2 response, such as septic shock or trauma (Trajkovic et al., Cytokine Growth Factor Rev. 15:87-95, 2004; Brunner et al., Intensive Care Med. 30:1468-1473, 2004). Furthermore, interleukin-33/ST2L signaling represents a crucial cardioprotective mechanism in case of mechanical overload (Seki et al., Circulation Heart Fail. 2:684-691, 2009; Kakkar et al., Nat. Rev. Drug Discov. 7:827-40, 2008; Sanada et al., J. Clin. Invest. 117:1538-1549, 2007). An elevation in human soluble ST2 is also predictive of worse prognosis in patients with heart failure (HF) and those with myocardial infarction (Kakkar et al., Nat. Rev. Drug Discov. 7:827-40, 2008; Weinberg et al., Circulation 107:721-726, 2003; Shimpo et al., Circulation 109:2186-2190, 2004; Januzzi et al., J. Am. Coll. Cardiol. 50:607-613, 2007; Mueller et al., Clin. Chem. 54:752-756, 2008; Rehman et al., J. Am. Coll. Cardiol. 52:1458-65, 2008; Sabatine et al., Circulation 117:1936-1944, 2008). Elevated levels of human soluble ST2 are also predictive for death of a subject within one year (see, for example, WO 07/127749). Taken together, human soluble ST2 has been implicated in certain inflammatory diseases and the cardioprotective paracrine system, and is a predictive marker for prognosis in patients with heart failure and for death of a subject within one year.